Cosmic Threats

Professor Arnon Dar

The most violent stellar events in the Universe observed by astronomers at large distances may take place at sufficiently close distances to affect severely the terrestrial environment and even cause major mass extinctions on planet Earth. Such events include supernova (SN) explosions, long and short gamma ray bursts (GRBs), and eruptions of anomalous pulsars and microblazars. Their possible effects on the terrestrial environment and their direct threat to life will be discussed. The credibility of such threats will be tested by examining whether such violent astrophysical events could have been responsible for some of the major mass extinctions which took place on planet Earth and were documented relatively well in the geological records of the past 500 million years.